The present invention relates, in general, to semiconductor device handlers, and more particularly, to a handler for testing packaged semiconductor devices.
In the past, the semiconductor industry had used testers which evaluated packaged semiconductor devices individually in a serial fashion. These testers had individual handlers which supplied devices to the tester one at a time. These previous handlers had comparatively low throughput.
As electronic technology improved, tester electronics became faster than the handlers which supplied them. This results in inefficient use of the tester as the electronics remain idle while the handler transports devices. A partial solution is achieved by parallel testing where a number of devices are tested at one time. Further improvement in handling efficiency is achieved by batch handling where several packaged devices are transported to and from the tester electronics grouped together in boats or device carrier trays.
One disadvantage of existing batch handlers is that the boats are moved via a system of cables and pulleys. The boats are not rigidly attached to the cable, so movement is relatively slow. Also, precise positioning of the boat is difficult and frequent maintenance and adjustment is required. As the cables age they stretch, requiring frequent realignment and maintenance.
Another disadvantage of existing batch handlers is that pick and place equipment is required to transfer packaged devices from the transport boat to the tester electronics. Pick and place equipment is also needed to remove tested devices from the tester and return them to the boat. This transfer operation not only increases equipment complexity, but also consumes a large amount of time while the tester electronics remains idle.
An additional disadvantage of available batch handlers is that the handling mechanism remains idle during the testing operation. Packaged devices are emptied from the transport boat during test, so the boat remains idle waiting for the return of the devices before it continues. The nature of the handling and testing operations remains essentially a serial process in currently available handlers.
Accordingly, it is desirable to have a batch handler for packaged semiconductor devices where the devices can be inserted as group into the tester. It is also desirable to have a handler which operates in parallel with the tester so that handling operations are performed during the testing operation, and the tester is operating during a large portion of the handling time.